1. Field of the Invention
The field of the present invention relates generally to billiard table frame construction, more particularly to such construction incorporating threaded means for leveling the bed, and most specifically to wood frame billiard table construction incorporating threaded means for leveling a slate bed.
2. General Background
Leveling the playing surface of a billiard table is generally regarded as a difficult matter requiring either:
(a) lifting an end of the table and modifying the effective length of a leg, checking for level, and modifying the effective length of a leg again until level is obtained; or PA0 (b) lifting the bed of the table from the frame in order to shim between the two. PA0 (a) independent of the condition of the floor surface under the table; PA0 (b) capable of achieving high precision leveling of the bed; PA0 (c) readily applicable to a wood frame construction; PA0 (d) of ample strength for a full inch thick slate bed; PA0 (e) operable at any time without any disassembly of the table; PA0 (f) operable with ordinary, readily available, tools; PA0 (g) durable; PA0 (h) unobtrusive; and PA0 (i) economic.
It is considered that threaded ends to the legs might be used to facilitate the modification of the effective length of the legs, however, such leg ends are not easily constructed to possess the relatively large amount of floor contact area desired of a billiard table, especially one with a slate bed which is generally considered the conditio sine qua non of a good billiard table which is, intentionally, quite massive.
For this reason shimming the legs is considered to be the most prevalent approach to leveling in which case an end of the billiard table must be lifted and the operation is further typically repetitive in obtainment of a level surface. Lifting an end of a billiard table properly requires an appropriate jack and is inherently potentially adverse to the structure of the table as weight is shifted at an angle to the legs on the other end. Lifting the entire table, alternatively, requires elevation of both sides and both ends simultaneously in order to avoid an imbalance which could readily result in damage to the table.
Similar considerations apply to lifting the bed from the frame as the bed, which is preferably slate, is quite massive. Partial disassembly of the table is also required in this approach and both knowledge and experience are considered invaluable in this operation. Lifting an end of the table and modifying leg length is hence considered the more prevalent approach. In either case both a slate bed and a good billiard table are necessarily massive and therefore difficult to lift which is generally considered an obstacle to leveling the playing surface of a good billiard table possessing a slate bed.
Rather than lifting the bed or an end of a billiard table or using threaded leg ends it is considered that threaded means for elevational adjustment in support of the bed could more easily enable effective leveling of the playing surface of a billiard table. While this approach is considered relatively obscure in the current market there are references known utilizing threaded means for elevational adjustment of the bed of a billiard table as discussed immediately below.
3. Discussion of the Prior Art
U.S. Pat. No. 167,540 issued to Joergens for a `Billiard-Table` on Sep. 7, 1875 discloses the use of winged screws butting against slightly inclined laterally disposed end frame members for the apparent purpose of modifying the elevation of either end of a cast metal frame billiard table.
U.S. Pat. No. 170,557 issued to Held for a `Billiard-Table` on Nov. 30, 1875 discloses the use of "screws J J', in combination with the frames C C' E and legs D, for leveling the bed of a billiard-table". Each screw is rotatably trapped within a collar fixed to the lower frame C' and threads through a plate mounted on the underside of the upper frame C into a blind cavity to accommodate the vertically displaceable enclosed upper end of the screw which further extends downward below the underside of the lower frame C' in a square cross section apparently intended to facilitate the application of torque by a wrench.
U.S. Pat. No. 1,715,631 issued to Treiber on Jun. 4, 1929 for a `Game Table` discloses "(v)ertically disposed adjusting screws 12 (which) are screw-threaded through the horizontal" (Column 2, Lines 89-90) members of a lower frame "adapted to abut the lower surface of" (Column 2, Lines 94-95) horizontal members of an upper frame, the frames being comprised of angle iron and other iron bars and sheet metal bolted together.
U.S. Pat. No. 1,860,215 issued to Young on May 24, 1932 for a `Leveling Device for Pool and Billiard Tables` discloses vertically oriented adjusting screws 40 with "flattened wings 43" for manual application of torque "positioned at intersections of the braces 30 and reenforcing bars 20 (which) at their upper ends are provided with swivel plates 45" affixed to the upper reenforcing bars 20, preferably by extending a reduced portion of the screw through an aperture in the plate which is "headed over to prevent axial displacement" (Column 2, Lines 76-94).
U.S. Pat. No. 3,658,328 issued to Kooker on Apr. 25, 1972 for `Pool Game Tables and Components For Use Therein` discloses a table of cast concrete construction comprising a lower pedestal section and an upper table top section connected by a central tubular telescoping component through which billiard balls feed and which maintains the upper and lower section in alignment, the upper section being supported by a plurality of vertically oriented leveling screws mounted in the upper end of the lower pedestal section and simply abutting the lower face of the upper table top section.